The Court of Appeals of California determined that there is no violation of a claimed biological father’s constitutional rights if he is denied the right to bring a paternity action for a child born within 300 days of the mother's divorce from another man. The child in this case was conceived while Mother was married but separated from Husband, was born after Mother's divorce, and was being raised by Mother and her ex-husband. The claimed biological father brought a paternity action, which the trial court moved to quash on the grounds that he was not a presumed father under the paternity code. Biological father argued that applying the statutory paternity presumptions and standing requirements to deprive him of the opportunity to establish his paternity would violate a liberty interest protected by the United States Constitution.

The court reviewed thoroughly the case law on the subject, noting considerable uncertainty in the issue of when a claimed biological father may have a constitutional right to bring a paternity action even though not a presumed father. The court commented that, “The uncertainty likely will continue in the near future because the so-called nuclear family, on which many of our paternity laws are based, now resembles more of an electron field.” Summarizing the status of the law to date, the court concluded that, while biological fathers who have developed an existing relationship with a child have a protected liberty interest, the interest asserted by the claimed biological father here was merely an "opportunity interest," which is not constitutionally protected except, perhaps, in the rare situations in which marital parents are either dead or have relinquished an interest in the child by placing the child for adoption by third persons.